Istanbul (Reuters), May 1: Two police officers were killed and 23 people wounded in a car bomb attack on police headquarters in the southeastern Turkish city of Gaziantep, the provincial governor and police sources said, in one of two attacks on security forces on Sunday.

There was no immediate claim of responsibility; but Turkey has suffered attacks recently both from Kurdish militants and Islamic State fighters, raising uncertainty at home and among NATO allies about spillover of conflict from neighboring Syria.

A bomb-laden vehicle was detonated outside the gates of police headquarters on a street housing several other provincial government buildings whose windows were shattered.

Footage from broadcaster CNN Turk showed forensics experts collecting pieces of the wrecked vehicle as well as rubble strewn by the blast felt across the city.

Police cordoned off the scene and police carrying rifles patrolled the area. Gunfire was heard at the time of the explosion and a second car was reported to have been driven away from the scene, CNN Turk’s correspondent said.

Nineteen police officers and four civilians were wounded in the attack, a statement from Gaziantep governor Ali Yerlikaya’s office said. One police officer died at the scene and a second in hospital, a security source said.

MULTIPLE THREATS

Several hundred miles eastwards along the same border, in the town of Nusaybin, three Turkish soldiers were killed and 14 others wounded in an armed attack by Kurdish militants during a military operation, an army statement said.

Turkey is facing security threats on several fronts. As part of a U.S.-led coalition, it is fighting Islamic State in neighboring Syria and Iraq and battling Kurdish PKK militants in its southeast, where a 2-1/2-year ceasefire collapsed last July, triggering the worst violence since the 1990s.

Police officers inspect the scene after an explosion in front of the city’s police headquarters in Gaziantep, Turkey May 1, 2016. Ihlas News Agency via REUTERS

Turkish military sources said on Sunday drones from the U.S.-led coalition had struck an Islamic State explosives depot in the northern Syrian town of Dabiq, drawing on intelligence from Ankara. Two Islamic State militants outside the building were killed and several others were thought to have been inside.

The province of Gaziantep, bordering Islamic State-held Syrian territory, is home to a large Syrian refugee population and there have been several police raids on suspected Islamic State militants there over the past months.

A wave of suicide bombings this year, including two in its largest city Istanbul, have been blamed on Islamic State, and two in the capital Ankara were claimed by a Kurdish militant group.

Last week a female suicide bomber blew herself up next to a mosque on a busy street in Turkey’s fourth largest city of Bursa, wounding eight people.

Turkey has also faced attacks from far-left groups, mostly on police and security forces.

The town of Kilis just across from Syria has also been increasingly targeted by Islamic State rockets over the past few months. On Sunday, three rockets wounded two people. More than 50 rockets have landed killing 18 people since January.

Hurriyet newspaper reported that four suspected Islamic State militants plotting an attack on May Day celebrations in Ankara had been detained by counter-terrorism units overnight.